The present invention relates to a connector and a radiation tomographic imaging apparatus, and particularly to a connector applied to detecting means in which a plurality of detector elements for detecting radiation and outputting projection data are disposed, and a radiation tomographic imaging apparatus employing such a connector.
Known radiation tomographic imaging apparatuses include an X-ray CT (computed tomography) apparatus that employs X-ray radiation to produce an image representing a cross-sectional plane of a subject to be imaged. The X-ray CT apparatus is used in a wide variety of applications including medical and industrial applications with a human body or an inanimate object as a subject to be imaged.
The X-ray CT apparatus scans the subject to be imaged around the body axis of the subject to be imaged, and employs an X-ray tube to irradiate the subject to be imaged with X-rays in a plurality of view directions, for example. An X-ray detector in which detector elements for detecting X-rays are disposed detects X-rays passing through the subject to be imaged in the plurality of view directions for each view direction, and outputs projection data from electrodes connected to the X-ray detector. Then, a data collecting section having a board on which a driving circuit is formed to collect projection data collects the projection data output by the electrodes connected to the X-ray detector from electrodes on the board. Based on the collected projection data, a tomographic image of an imaged region in the subject to be imaged is reconstructed and produced.
The imaged regions in the subject to be imaged and the purposes of imaging with the X-ray CT apparatus are becoming increasingly diverse in recent years, and accordingly, the X-ray CT apparatus is required to have improved image quality including resolution, and increased imaging speed. To respond to such requirements, the X-ray CT apparatus has an X-ray detector in which a plurality of detector elements are arranged in the form of an array to obtain a plurality of tomographic images during one scan rotation around the subject to be imaged, and the number of arranged detector elements is on the increase. (For example, see Patent Document 1).
[Patent Document 1] Japanese Patent Application Laid Open No. 2003-33344.
Such an X-ray detector has a plurality of X-ray detector modules in each of which a plurality of detector elements for detecting X-rays are arranged in the form of an array, and to facilitate manufacture, the plurality of X-ray detector modules are arranged side by side in both the channel direction and body axis direction. Moreover, in the X-ray detector, the plurality of detector elements are arranged at high density to improve resolution, and the electrodes for outputting projection data from the detector elements to the data collecting section are also disposed at high density because they are formed in a limited region.
Similarly, in the data collecting section for collecting projection data output from the X-ray detector, a plurality of boards on which driving circuits for collecting the projection data are mounted are disposed corresponding to the plurality of X-ray detector modules making up the X-ray detector, and the electrodes to which the projection data is input are formed on the each board at high density corresponding to the density increase of the electrodes for outputting the projection data from the X-ray detector elements.
When the electrodes in the X-ray detector and those on the boards in the data collecting section are connected to one another, the conventional method has been to use thermal compression bonding or connectors, for example.
With the conventional thermal compression bonding, however, the increased compactness of the electrodes reduces the space available for the connection work, and it becomes difficult to connect the electrodes to one another at high precision. With the conventional connectors, the high compactness of the electrodes makes it difficult to connect between the electrodes and to fix the boards on which the electrodes are formed to the connector with sufficient rigidity.
Moreover, when maintenance is carried out on an X-ray detector array constituted of a plurality of X-ray detector modules, it suffices to replace only the one malfunctioning X-ray detector module in the small space where the plurality of boards are disposed; but with the conventional connection by thermal compression bonding, the modules cannot be made removable, and with the conventional connectors, the space for insertion/removal work is small because the plurality of boards are present, and the insertion/removal work is difficult to do.
As described above, in the conventional X-ray CT apparatus, one example of a radiation tomographic imaging apparatus, as the number of detector elements in the X-ray detector is increased in line with the need for improved image quality and imaging speed, the electrodes are arranged at higher density, and it becomes difficult to fix the boards to the connector with sufficient rigidity and to insert/remove the board into/from the connector because of the small space available for disposing the boards, which makes it difficult to do maintenance work.